To keep feet warm and dry in cold weather, particularly in snow or slush, people have wrapped their feet with plastic film, including bread bags and common household food wrap, before putting on socks. However, this technique is not useful for the remainder of the body. In recent years, the emphasis for cold weather and/or high altitude clothing has been on "waterproof and breathable" laminates. Water vapor molecules, from perspiration, will transfer through such fabrics, such as by a process of absorption, diffusion and desorption or by evaporation. Water vapor from perspiration will pass out but liquid water will not pass in. In breathable garments, the moisture goes to the outer insulation and adulterates it. The wet outer insulation causes evaporative heat loss, which can be severe. Furthermore, these fabrics include a wicking base, for the intended purpose of attracting the perspiration moisture to lead it to the breathable layer. Garments made of such a fabric tend to mask the degree of perspiration which the wearer is creating, thus hiding the commencement of dehydration, which can lead to high altitude sickness, including cerebral and/or pulmonary edema. Fabrics of this type are disclosed in the following U.S. Pat. Nos.: 4,194,041, 4,845,862, 4,898,761, 5,126,182, 5,204,156, 5,268,212, 5,364,678, and 5,435,014.
In U.S. Pat. No. 4,502,153 there is disclosed a garment liner having a vapor barrier adjacent opposite surfaces of a layer of insulating material, to keep the insulating material dry.
Another known garment utilizes two layers of fleece having a breathable barrier layer in between. Because of the weight of the inner fleece lining, this garment will absorb significant perspiration, thereby masking the onset of dehydration, and the garment will not dry quickly between use, therefore remaining wet and cold. Since the inner fleece is wet, it provides no insulation whatsoever.
A shirt or vest having a layer of thin tricot laminated to a thin flexible polyurethane film has been found to be insufficiently durable, due to delamination of the film from the tricot, tearing of the film, and loss of patches of film from the tricot.